The bosun's chair hitch, or lowering hitch, and how to form it

[benz]

If I had to pass a bight of rope around my entire body while securing myself with the other hand I would probably let the wrong hand go and end up hanging myself. There is a device rockclimbers use commonly called a grigri (made by Petzl). Once the rope ( 3/8 is the best diameter; I usually run a piece of it up with a halyard when I need to climb a mast), is threaded, you pull a lever to lower off. Releasing the lever stops the descent. That way I can stop anywhere along the length of the mast, with no outside assistance. It can be fitted to a bosun's chair, but I prefer going up a mast in a climbing harness anyway, since I use mechanical ascenders (also made by Petzl) for that sort of thing. Incidentally, I found it handy to be able with the ascenders to go up the mast while under sail by jugging the tensioned fall of the main halyard (external halyards are a must for this; but external halyards should be a must anyway) to spot for coral when sailing in those parts of the world where coral is found.
If you do a lot of mast climbing, these little climbing gadgets are really worth looking into.
Ben